Bad Service - No aftercare Service

I bought a Defy Gas Stove a moth ago. I noticed the Oven Dor was not fited correctly.

When I phoned the branch who sold me the stove ,I was told by the "Service Department " at Diep River that they could not assist as I required a Gas Compliance Certificate . This is not a new connection - neither was I told that a " Compliance Certificate " is required prior to me purchasing the stove , furthermore , that my stove door would not be under guatrentee . Yet on the invoice it states 3 year guarentee - no mention of a gas compliance .